Chunks don't load and you get stuck.

I was playing in the new version, and when i was in the nether the chunks stop loading and i could see through the walls, like xray (i had the chunks at 48), i preseed f3+A but it didn't work, i lowered the chunks and left the world but these bugged chunks still there.

 

(Solved, it was because i was playing with Optifine)